1. Field of the Invention
The present invention relates to an image reading and recording apparatus for optically reading an image from an image carrying medium and for optically recording the read image onto a recording medium.
2. Description of the Related Art
A facsimile machine is known which has a copying function by incorporation of a laser beam printer. Such a facsimile machine comprises a reading section for optically reading an image from an image carrying medium for output of image signals, a recording section for generating and controlling a light beam to record the read image onto a recording medium on the basis of the image signals, a record timing signal generator for detecting the light beam at a predetermined position and for generating a record timing signal which determines start timing for control of the optical beam.
In the conventional facsimile machine described above, the image data read by the reading section are temporarily stored in a memory for each page, and the stored image data are then read out by the recording section successively on a line-by-line basis. Such temporary storage of the optically read image is necessary because the polygon mirror used for scanning the laser beam in a primary scanning direction is unstable or inaccurate with respect to its rotational cycle and therefore makes it difficult to synchronize the read timing with the record timing.
Thus, with the conventional facsimile machine, the need for temporary storage of the optically read image makes it necessary to provide a separate memory for such a purpose, thereby increasing the cost of the facsimile machine. Particularly, when the image data in multiple gradations need be stored, the capacity of the memory must be correspondingly increased to make the problem of cost increase even more remarkable. Further, the provision of such a memory necessitates access to that memory both the time of storing and reading out the image data, consequently prolonging the time required for copying.